1. Field of the Invention
The present invention relates to a transceiver module for optical communications.
2. Description of Related Art
There have been provided transceiver modules for optical communications which are compliant with the IEEE802.3ae standard, for example. A transceiver compliant with the IEEE802.3ae standard includes, for example, an NV (Non-Volatile) register, a DOM (Digital Optical Monitoring) register, an LASI (Link Alarm Status Interrupt) register, etc. which are XENPAK (common specifications of optical connectors and optical transceivers which operate according to the XAUI (10 Gigabit Attachment Unit Interface) protocol adopted by 10 Gbit Ethernet (registered trademark) defined by the IEEE802.3ae standard) (refer to nonpatent reference 1, for example).
A related art transceiver IC (referred to as a PHY IC from here on) which constitutes such a transceiver module mentioned above has both IEEE registers which are used when carrying out communications processing and XENPAK registers which are defined by the above-mentioned standard, those registers being implemented via hardware. As error-associated registers which belong to those registers, there exist interrelated registers (i.e., LASI_Status registers) holding the same contents in the IEEE registers and XENPAK registers, respectively.
[Nonpatent Reference 1]
“A Cooperation Agreement for 10 Gigabit Ethernet (registered trademark) Transceiver Package Issue3.0”, [online], 18 Sep. 2002 and XENPAK, [retrieved on Sep. 17, 2004], Internet URL <http://www.xenpak.org/MSA/XENPAK_MSA_R3.0.pdf>
In the related art transceiver module, when a change is made to the structure and function of either the IEEE registers or the XENPAK registers, it is necessary to perform the design and development of the PHY IC again so that the structure and function of the registers meet new specifications.
On the other hand, when the structure and function of the XENPAK registers which are built in the PHY IC are software-emulated by a device control unit (referred to as a DCU from here on) which is an IC for controlling the PHY IC and other peripheral functions, the structure and function of the XENPAK registers can be changed by changing a software program of the DCU which software-emulates the structure and function of the XENPAK registers.
However, while information about a high-speed error which is detected only by the PHY IC and which is associated with communications processing is stored in one of the XENPAK registers of the PHY IC, to which information about errors can be set, information about a low-speed error which is detected only by the DCU and which is associated with internal processing is stored in one of the XENPAK registers of the PHY IC, to which information about errors can be set. A problem is therefore that a mismatch occurs between the contents of the register for storing error information in the PHY IC and those in the DCU.